Fig. 1 Soil water distributions in the 0–300 cm soil layer under different combined N and P treatments at the winter wheat harvest and summer maize harvest. The codes comprising 201706, 201806, and 201906 denote data collected at the winter wheat harvests in 2016–2017, 2017–2018, and 2018–2019, respectively. The codes comprising 201710, 201810, and 201910 denote data collected at the summer maize harvests in 2017, 2018, and 2019, respectively.